1. Field of the Invention
The present invention relates generally to the controlling of the execution of a watering program by an irrigation controller.
2. Discussion of the Related Art
Rain sensors for use in the interruption of programmed watering schedules of an irrigation controller are generally known to include a material that is responsive to rain, and in the event a preset level of rain is exceeded, a switch is activated which outputs a signal to the irrigation controller that causes the controller to cease the execution of watering schedules.
U.S. Pat. No. 6,452,499 to Runge et al. (which is incorporated herein by reference) describes a wireless rain sensor that uses a hygroscopic material that expands when exposed to water. When the hygroscopic material expands beyond a specified point or threshold, an integrated transmitter wirelessly transmits a radio frequency signal to a receiver attached to the controller. The receiver receives the wireless signal and causes the controller to cease watering. Similarly, U.S. Pat. No. 6,977,351 to Woytowitz (which is incorporated herein by reference) describes a wireless rain sensor including a hygroscopic material that is not mechanically connected to the switch that triggers the transmission of the wireless signal that will cause the interruption of watering The threshold level may be adjusted by a user through the mechanical adjustment of the distance the hygroscopic material must expand before actuating the switch, such as described in U.S. Pat. No. 6,570,109 to Klinefelter et al (which is incorporated herein by reference). Thus, in order to exceed a selectable threshold, the hygroscopic material must expand a selectable distance, which corresponds to a selectable level of rain fall.